Methods of preparing tri-esters of thiophosphoric acids



2,802,856 METHODS OF PREPARING T'ni-EsTERs or THIOPHOSPHORIC AC-lDSGeorge R. Norman, Cleveland, William M. Le Suer, Euclid, and Thomas W.-Mastin, Cleveland Heights, Ohio, assignors to The Lubriz'ol Corporation,Wicklilfe, Ohio, a corporation of Ohio No Drawing.- ApplicationSeptember 8, 1953, Serial No. 379,097

4 claims. c1. 260461 This invention relates to the method of producingtriesters of thiophosphoric acids and more particularly to thepreparation of arenas of thiopho sphoric acids in which one of the esterradicals contains less than 4 carbon atoms in a straight chain.

It is known that di-organo thiophos'phoric acids react with unsaturatedorganic compounds, if the unsaturated linkage occurs in an essentiallystraight carbon atom chain which has at least 4 carbon atoms, or if theunsaturated linkage is activated by an activating substituent. Either ofthese requirements has been found necessary by prior investigators forthe reaction to occur. This invention is concerned with the discoverythat thiophosphoric acids react with unsaturated hydrocarbons havingless than 4 carbon atoms in a straight chain, without any activatingsubstituent groups, and without any catalysts, under certain specialconditions of temperature and pressure.

It is, therefore, an object of this invention to provide a process forthe preparation of tri-es'ters of thiophosphoric acids by the reactionof di-organo thiophosphoric acids with unsaturated hydrocarbons havingless than 4 carbon atoms in a straight chain, said unsaturatedhydrocarbons being free from reactive substituent groups.

It is a further object of this invention to provide a novel process forthe preparation of tri-esters of thiophosphoric acids.

Other objects and advantages will become apparent as the followingdescription proceeds.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described andparticularly pointed out in the claims, the following descriptionsetting forth in detail certain illustrative embodiments of theinvention, these being indicative, however, of but a few of the variousways in which the principle of the invention may be employed.

Broadly stated, this invention relates to the method of producingtri-ester's of thiophosphoric acids which comprises reacting: (a)thiophosphoric compounds of the fol lowing structure:

wherein A is selected from the class consisting of RO-, and RS, B isselected from the class consisting of R'O, and RS, and R and R" areselected from the class consisting of the same or dill erent organicradicals; with (b) unsaturated aliphatic hydrocarbons of at least 2carbon atoms having lessthan 4 carbon atoms in a straight chain, andhaving at least one unsaturated double bond; within a temperature rangefrom about 10 C. to about 200 C., under pressures of at least about 10pounds per square inch, in such proportions as to cause the reaction toproceed at a reasonable rate, and for a length of time such that theacidity of the mass is substantially reduced.

Although the s'toichio'rnetry of the process involves the Patented Aug.13, 1957 apparent to one skilled in the art that these proportions canbe altered. For example, it is usually desirable to employ an excess ofthe unsaturated reactant (b) so as to force the reaction to substantialcompletion. Using ethylene as reactant (b) for purposes of illustration,the reaction proceeds according to the equation: a, s A.\ s 1 21 B an sB I so ri'z om More particularly, this invention relates to the methodof producing tri-esters of thiophosphoric acids which comprisesreacting: (a) 0,0-di-organo dithiophosphoric acids of the followingstructure:

+ CHnlCHz RO sir wherein R and R are selected from the class consistingof the same or difierent organic radicals; with (b) olefins having lessthan 4 carbon atoms in a straight chain; within a temperature range fromabout 10 C. to about 200 C., under pressures oi at least about 10 poundsper square inch, in such proportions 'as to cause the reaction toproceed at a reasonable rate, and for a length of time such that theacidity of the mass is substantially reduced.

acid di estersv of pentavalent phosphorus which can be reactionof onemole of (a) with one mole of (b), it is more exactly defined by theformula:

I A, s

- r s an wherein A is selected irom class consisting of RO- and RS, Bisselected from ;the class consisting of R'O, and RS, afiglgand R? areselected from the class consisting of the same or different organicradicals, preferably hydrocarbon radicals of from 1 to 60 carbonatoms,.and most'desirably saturated non -benzenoid hydrocarbon radicalsot'froni 2, 't'o 3' 0 carbon atoms. Special pref' je isfgiv'cnto the0,0-di-organo dithiophosphoric acids having the formula; R()\ S it"o S Hwherein R and R are defined above.

In the following table will be" found examples of R and R inthe aboveformulae:

- TABLE 1 1. Alighatic radicals, for example:

lkyl radicals, e. g.

Methyl Ethyl Propyl (nand iso-) Butyl (n-, sec-, iso-, and tert-) Amy](nsec-, and tert-) Hexyl rad cals, e. g. n-Hexyl Sec-beryl2,2-dimethyl-3-buty1 2,2-dimethyl-4-buty1 2,2-dlmethyl-2-buty1 -metny-p.en y1 2 'methyl-2-penty1 3-methyl-1-pentyl 3-methyl-2-penty1, etc.

Heptyl n -Hepty1 See-heptyl 4 2,3-dimethyl-3-penty12,4-dimethyl-2-pentyl 2,4dlmethy1-3-penty1 2,2,3-trimethyl-3-buty13-ethyl-2- entyl a-methyl- -hexy1; etc.

radicals, e. g.

mrinoisopropyl-alpha-hydroxy naphthyl radi caPoly-propyl-hydroxy-naphthyl radicals, e. g.din-propyl-beta-hydroxy-naphthyl radicals Alkyl-chlaro-aryl radicals, e.g.

Methyl monochloro-phenyl radicals Methyl-po1ych1oropl1enyl radicals, e.g.: Methyl-dichloro-phenyl radicals Methyl-trichloro-phenyl radicalsEthyl-menochloro-anthracyl radicals, e. g.Ethyl-monochloro-alpha-anthracyl radicalsTriethyl-monochloro-beta-anthracyl 1' C3. Ethylpdiybhloro-anthracylradicals, e. g.:

Ethyldicl1loro-alpha anthracyl radicals'Dicthyl-trichloro-beta-anthracyl radL C8. S Alkyl-nitroaryl radicals,e. g.:

Methyl-nitro-phenyl radicals Dimethylnitro-phenyl radicalsEthyl-dinitro-phenyl radicals Butyl-nitro-naphthyl radicals, e. g.

Tert-butyl-nitr-naphthyl radicals Sec-butyl-dlnitro-naphthyl radicalsPropyl-nitro-phenanthryl radicals. e. g.

Isopropyl-dinitro-phenanthryl radicals Di-n-propyl-dinitro-phenanthrylradicals The di-organo thiophosphoric acid materials used in thisprocess can be prepared by well known methods.

The 0,0-di-0rgano dithiophosphoric acids can be prepared, for example,by reacting organic hydroxy compounds with phosphorus pentasulfide.Suitable organic hydroxy compounds include alcohols, such as, alkanols,alkandiols, cycloalkanols, alkyland cycloalkyl-substituted aliphaticalcohols, ether alcohols, ester alcohols and mixtures of alcohols;phenolic compounds, such as, phenol, cresol, Xylenols, alkyl-substitutedphenols, cycloalkylsubstituted phenols, phenyl-substituted phenols,alkoxyphenol, phenoxy phenol, naphthol, alkyl-substituted naphthols,etc. The non-benzenoid organic hydroxy compounds are generally the mostuseful in the preparation of the 0,0-di-organo dithiophosphoric acids. Afull discussion of the preparation of these compounds is in the Journalof The American Chemical Society, volume 67, (1945), page 1662. V

The S,S-di-organo tetrathiophosphoric acids can be prepared by the samemethod described above, except that mercaptans are employed in place ofthe organic hydroxy compounds.

The O,S-diorgano trithiophosphoric acids can be prepared by the samemanner employed in thepreparation of the dithiophosphoric acidsdescribed above, except that a mixture of mercaptans and organichy'droxy compounds is reacted with phosphoruspentasulfide.

UNSATURATED HYDROCARB ON MATERIALS PROCEDURE The reaction of thisinvention takes place at pressures greater than atmospheric in anautoclave, generally a stainless steel shaker type having athermostatically controlled heating jacket. Thethiophosphoric compoundis introducedinto the autoclave and the unsaturated hydrocarbonadinittedr If the unsaturated hydrocarbon is a gaseous compioiind, it isintroduced under pressure at room temperature. "However, the unsaturatedhydrocarbon can beJiq uefied, the autoclave cooled, and the liquidunsaturated hydrocarbon added thereto. Thereafter, the autoclave issealed, shaken, and the temperature raised- The increase in temperatureis accompanied with an increase inpressure in .theau'toclave which fallsofi as the reaction proceeds. The reaction can continue until drop inpressure remains constant, after which the reaction is considered to besubstantially complete. After completion of the reaction the autoclaveis cooled to room temperature, and any excess unsaturated hydrocarbonvented and the product removed.

The temperature of the reaction is generally within the range of fromabout 10 C. to about 200 C., preferably from about 50 to about 150 C.and most desirably from about C. to about 120 C. Pressures aboveatmospheric are necessary for'the reaction to occur. The pressures.employed are generally within the range of from about 10 to 5000 poundsper square inch, preferably from about 50 to 2500 pounds per squareinch, and most desirably from about'80 to about 1000 pounds per squareinch. The reactiontime is usually at least 0.5 hour or until the acidityof the mass is substantially reduced. Longer periods have no detrimentaleffects and in many instances increase in yield. As stated hereinbefore,stoichiometric amounts of reagents can be used, i. e., one mole each ofthe thiophosphoric compound and the unsaturated reagent; however,usually an excess amount of the unsaturated hydrocarbon is employed tocause the reaction to proceed to substantial completion rat a reasonablerate.

The present process may be further illustrated by the following exampleswhich are subject to certain obvious modifications and changes withinthe scope of the claims, and. therefore, are ,not to be construed aslimiting the scope of the invention, v Example I.-Preparation of0,0,S-trie thyl dithiophos- 0,0-diethyl dithiop'hosphoric acid (372grams, 2.0 moles) having an acid number of 295 (98% pure) was introducedinto. a stainless steel shaker type autoclave of 3800 ml. capacityhaving athermostatically controlled heating jacket. Ethylene gas wasadmitted until the pressure had risen to 500 pounds per square inch atroom temperature, and then the autoclave was shaken for 6 hours at 100to C. The pressure rose initially due to heating and then dropped as thereaction proceeded, the final pressure b'ein'g' 640pounds per squareinch at the reaction temperature employed.

After the autoclave was cooled to room temperature, the excess ethylenewas vented and the contents removed.

The acid numberof the crude product was found to be 92. This materialwas washed with about twice its volume of 5% aqueous NaOH and then withwater. The organic layer was separated, dried over anhydrous MgSOr, andfractionatedunder reduced pressure.

The purified product, a colorless liquid, was collected at 74 to 77 C./1 mm. Hg absolute pressure, and was 0,0,S-triethyl' ditliiophosphate.

Yield, 163 grams (38% of theory) Acid N0, 32.2 1 V 1 1.5033 1 4Calculated for C6H1502PS22 percent P, 14.46; percent 8,

29.92. -Eoundz percent-P, 14.25; percent S, 30.70.

9 had risen to 100 pounds per square inch at room temperature. Theautoclave was then sealed and shaken for hours at 100 to 115 C. Thepressure rose initially due to heating and then dropped as the reactionproceeded, the final pressure being 120 pounds per square inch at thereaction temperature.

The autoclave was allowed to cool to room temperature, the excesspropylene vented, and the contents removed. The acid number of the crudeproduct was 20.9.

The material was then purified in the same manner as set forth inExample 1. The purified product, a colorless liquid, was collected at 73C. to 77 C./1 mm. Hg absolute pressure.

Yield, 316 grams (69% of theory) Acid No., 1.0

Calculated for C7H1'1O2'PS2: percent P, 13.57; percent S,

28.09. Found: percent P, 13.83; percent S, 29.00.

Example 3.Preparati0n of 0,0,-di(2-ethylhexyl)-S- isopropyldithiophosphale 0,0 di (2 ethylhexyl) dithiophosphoric acid (354 grams)having an acid number of 154 was introduced into a stainless steelshaker type autoclave of 1320 ml. capacity having a thermostaticallycontrolled heating jacket. Propylene was admitted until the pressure hadrisen to 170 pounds per square inch at room temperature, and then theautoclave was sealed and shaken for 4 hours at 50 to 100 C. during whichtime the pressure rose to a maximum of 550 pounds per square inch. Thepressure decreased as the reaction proceeded.

The autoclave was cooled to room temperature, the excess propylene wasvented and the contents removed. The product (358 grams), a dark liquidhaving an acid number of 13. 4 was substantially pure0,0-di-(2-ethylhexy1)-S-isopropyl dithiophosphate.

Example 4.--Preparati0n of 0,0-di-(isopropylphenyl)- S-isopropyldithiophosphate 0,0-di-(isopropyl-phenyl) dithiophosphon'c acid (715grams) having an acid number of 122 was introduced into a stainlesssteel shaker type autoclave of 1320 m1. capacity having athermostatically controlled heating jacket. Propylene was admitted untilthe pressure had risen to 130 pounds per square inch at roomtemperature, and then the autoclave was sealed and heated for 5.5 hoursat 93 to 115.5 C. during which time the pressure rose to a maximumpressure 190 pounds per square inch. As the reaction proceeded thepressure dropped. When the pressure remained constant 80 pounds persquare inch) the reaction was considered substantially complete.

The autoclave was cooled to room temperature, the excess propylene wasvented, :and the contents removed. The product (774 grams), a darkliquid having an acid 10 number of 11, was substantially pure0,0-di-(isopropylphenyl) -S-isopropyl dithiophosphate. Example5.-Preparation of 0,0-diethyl-S-tertiarybutyl dithiophosphate0,0-'diethyl dithiophosphoric acid (1190 grams) having an acid number of274 was introduced into a stainless steel shaker type autoclave of 3800ml. capacity which had been cooled in a Dry Ice-acetone bath. Coldliquid isobutylene which had been previously cooled in a Dry Ice-acetonebath was added and the autoclave sealed. The autoclave was then heatedfor 6 hours at 96110 C.

The autoclave was cooled to room temperature, the excess isobutylene wasvented, and the contents removed.

The product, a light brown liquid having an acid number of 4.65, wassubstantially pure 0,0-diethyl-S-tertiary- 'butyl dithiophosphate.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims or the equivalent of suchbe employed.

We therefore particularly point out and distinctly claim as ourinvention:

1. The method of producing tri-esters of thiophosphoric acids whichcomprises reacting: (a) thiophosphoric acids of the following structureRO SH wherein R and R are the same saturated hydrocarbon radicalsselected from the class consisting of lower alkyl and lower alkyl phenylradicals, with (b) an olefin selected from the class consisting ofethylene, propylene, and isobutylene within a temperature range fromabout 10 C. to about 200 C. under pressure of at least about 10 poundsper square inch.

2. The method of claim 1 characterized further in that component (b) isethylene.

3. The method of claim 1 characterized further in that component (b) ispropylene.

4. The method of claim 1 characterized further in that component (b) isisobutylene.

References Cited in the file of this patent UNITED STATES PATENTS2,528,732 Augustine Nov. 7, 1950 2,565,920 Hook et a1. Aug. 28, 19512,565,92h Hook et a1. Aug. 28, 1951 2,578,652 Cassaday Dec. 18, 19512,630,451 Fletcher et a1 Mar. 3, 1953 2,632,020 Hoegberg Mar. 17, 1953

1. THE METHOD OF PRODUCING TRI-ESTERS OF THIOPHOSPHORIC ACIDS WHICHCOMPRISES REACTING: (A) THIOPHOSPHORIC ACIDS OF THE FOLLOWING STRUCTURE